Data centre

ABSTRACT

A data center ( 100 ) includes at least one rack room (in for example module  140 ) having a floor and a plurality of rack storage areas on the floor, each rack storage area being arranged to accommodate a plurality of racks ( 143 ) in which a plurality of rack-mountable electronic components may be housed, one or more controllable air circulation systems (in for example module  122 ), one or more cold aisles ( 144 ) in the rack room, each cold aisle being adjacent to a rack storage area, and one or more hot aisles ( 145 ) in the rack room, each hot aisle being adjacent to a rack storage area. There may be a large air duct, in the form of a personnel corridor ( 123 ), for transporting, under the control of the one or more air circulation systems, cooling air, above the floor, to the one or more cold aisles. The air supply corridor/duct ( 123 ) may have a height greater than 1.5 m above the floor and a cross-sectional area of at least 2 m 2  and a maximum dimension in the plane of the cross-section of less than 3 m.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/942,308, filed Aug. 13, 2013, which was a continuation ofU.S. patent application Ser. No. 12/851,771, filed Aug. 6, 2010, whichclaims the benefit of Application PCT/GB2010/000759, filed Apr. 15,2010, claims the benefit of International Application PCT/GB2009/051777,filed Dec. 29, 2009 and claims priority to United Kingdom ApplicationGB0909584.5, filed Jun. 3, 2009; each of these applications beingindividually incorporated in its entirety herein by reference.

BACKGROUND OF THE INVENTION

The present invention concerns data centres, a method of coolingequipment in a data centre and also subject matter ancillary thereto.More particularly, but not exclusively, this invention concerns datacentre buildings, for example provided in modular form. The inventionalso concerns a data centre building, a method of cooling electronicequipment in a data centre building, a method of constructing a datacentre building, a method of extending an existing modular data centrebuilding, a rack room building module for building a data centre, and adoor arrangement for use within a building, for example a data centre.The invention also concerns a method of constructing a data centre in aspace within a building.

A data centre is a late 20^(th) Century development that has grown as aresponse to the increasing demand for computer processing capability anda recognition of the importance of IT in the place of every business andorganisation today. Whereas smaller organisations have sufficientprocessing power with laptops, PCs and occasionally servers, largerorganisations require higher capacity centralised processing to serve awide range of needs and applications. A few years ago this capacity wassupplied by large mainframe computers, but more recently the method usedhas been to provide data centres comprising many networked computerservers known as “blades” installed in racks enabling controlled andmodular expansion of capacity. The racks also typically housetelecommunications equipment such as routers to handle data flow betweenthe computer servers and data flow between the data centre and theoutside world.

Data centres can mirror the growth and business activities of successfulcompanies. The growth of a data centre within in an expanding companymay typically work as follows:

-   -   1. Initially the data centre may start as single rack of servers        in an air conditioned room—sometimes referred to as a ‘data        closet’.    -   2. As the organisation expands and along with it the number of        IT racks employed, the closets become ‘Server Rooms’ or ‘IT        Rooms’.    -   3. Eventually the number of racks and size of room expands,        often to the point where a dedicated building or part of a        building houses the IT. Whilst there is no strict definition of        when the size of an IT facility becomes large, or sophisticated,        enough to be termed a “data centre”, data centres are typically        relatively large IT facilities providing robust and resilient IT        facilities. Typically, there will be more than 50 servers (often        many more) and at least some redundancy in the power supply        powering the servers to ensure continuity of service.    -   4. As the company grows and/or becomes a multi-national        organisation additional data centres will be built and sometimes        numbers of these will be consolidated into ‘Super Data Centres’.

Data centre facilities can require a floor space ranging from a fewhundred square feet to a million square feet. The most prevalent sizefor a small data centre is five to ten thousand square feet with fiftyto a hundred thousand square feet being the most common floor arearequirement for a large data centre.

Data centres will typically have the ability to deliver applicationsspread across an organisation and/or supply chain and/or customers indiffering geographical locations. There will typically be a dedicatedmechanical and electrical (M&E) plant to deliver power, cooling and firesuppression with built-in redundancy with the aim of providing nearcontinuous operation. The M&E plant may be located separately from theIT equipment to enable appropriately qualified engineers to work oneither the M&E plant or the IT equipment independently of the other(thus improving security).

The IT industry has long recognised the criticality of central computingfacilities and the need for energy efficient operations to control costeffectiveness. Current data centre technology is the summation of 30years of innovation and engineering design thought and has come a longway in recent times. One key problem faced is how to cool a data centreeffectively and efficiently. As explained above, a data centre can growover time according to demand. As a result the following can happen:

-   -   1. A building is created, or a room within a building is        allocated to IT. An electrical sub-system of conditioned        (Clean′) power is run out to the IT room and the building's air        conditioning system is adjusted to cool that room.    -   2. As the data room grows in scale, IT racks are laid out in        rows. More IT products lead to more heat produced and so        increased ventilation and air conditioning is required.        Typically CRAC (Computer Room Air Conditioning) units are added        to the end of the rows to provide the cooling. Air produced by        these units is entrained through a raised floor and exits        through floor grilles at the front of the IT rack rows. The IT        products installed in the racks contain integral fans which draw        the cooled air from the front across the circuitry and heat is        exhausted via vents in the products to the rear. The separation        created by these IT racks creates a ‘hot aisle’ into which air        is expelled by the IT products in the racks and a ‘cold aisle’        from which cooler air is drawn into and through the IT products        by their integral fans.    -   3. Dedicated M&E plant may be required. The M&E plant is sized        based on an assessment of the future business requirements (over        the next decade for example). Direct expansion (DX) or chilled        water cooling plant is used to chill the air distributed within        the data centre. Typically a ‘set-point’ is created to maintain        the room at 21 Celsius, allowing for IT heat output and/or        external ambient conditions.

The way in which cooling is effected in purpose built data centres oftenresults in a similar arrangement. Thus, the equipment in the data centreis prevented from over-heating by means of introducing cool air into theroom. A typical arrangement of the prior art is shown schematically inFIG. 1 of the attached drawings. Thus, the data centre includes a rackroom 1 defined by walls 2 in which two sets of racks 4 for IT equipmentare accommodated. The IT equipment in the racks 4 generate heat,represented by dark arrows 6. The cooling of the IT equipment isachieved by introducing cold air into the room by means of airconditioning units, the cold air being represented by light arrows 8.

The drive for more efficient use of power has given rise to a need tomake the cooling used in data centres more efficient, as cooling ofequipment typically contributes significantly to the power used by adata centre. The efficiency of a data centre may be measured by means ofa quantity known as the Power Usage Effectiveness (PUE), which is theratio of the total energy used by a data centre, including IT equipment,and the energy consumed by the IT equipment only. If the power consumedby a data centre were 2.5 MW of which only 1.0 MW powers the ITequipment, then the PUE would be 2.5 (which represent an average PUE fora typical data centre). The closer to unity the PUE is, the moreefficient the data centre is. It is currently estimated that the moreefficient data centres currently installed operate at a PUE of about1.6.

In recent years, approaches such as adding baffles across the top of thehot and/or cold aisles, with doors or further panels across the end ofthe aisle to contain entrainment of the air have been made, leading todebate about whether it is more effective to ‘contain’ the cold aisle orthe hot aisle. A baffle arrangement is for example proposed in WO2006/124240 (American Power Conversion Corporation).

Some recent configurations have utilised a new generation of ‘in-row’cooling units in-between the racks, or, attached to the rear rack door.These bring the advantage of concentrated cooling but carry a high riskof refrigerant leakage. A slightly different arrangement, potentiallysuffering from similar problems is described in EP1488305. EP1488305discloses a plurality of cabinets forming a data centre, each cabinethousing a rack of IT equipment and each cabinet comprising an equipmentcooling unit within the cabinet to provide cooling.

The data centre industry is also suffering from being unable to meetdemand sufficiently quickly and from reacting to the need to make suchdata centres energy and space efficient. IT capacity has grown at anexponential rate, doubling about every 18-24 months, in the last 30years. Cooling capacity and space limits are frequently and repeatedlyreached creating significant bottlenecks in IT businesses. Building anew data centre to alleviate such bottlenecks and meet demand is timeconsuming. Traditional methods of constructing data centres can take upto 2 years to completion. Also, data centres are physically becominglarger year on year because current design and engineering practiceseeks to deal with heat issues by assuming low rack density andspreading IT thinly across large numbers of racks or large volumes ofspace.

The present invention seeks to provide an improved data centre and/or animproved method of, or means for, cooling a data centre. Additionally oralternatively, the invention seeks to provide a data centre and/or amethod of, or means for, cooling a data centre that mitigates one ormore of the above-mentioned disadvantages.

SUMMARY OF THE INVENTION

The present invention provides a data centre building including:

-   -   at least one rack room,    -   one or more controllable air circulation systems,    -   one or more cold aisles in the rack room,    -   one or more hot aisles in the rack room, and    -   an air supply corridor for transporting cooling air, above the        floor, to the one or more cold aisles.

The air supply corridor may function also as a personnel accesscorridor. The air supply corridor may have a height greater than 1.5 mabove the floor.

The data centre building may be a building in which all the interiorspace is taken up by the data centre. Of course, alternatively, the datacentre building may be a building in which only part of the interiorspace is taken up by the data centre, with the rest of the interiorspace being available for other uses.

Each rack room may have a floor and a plurality of rack storage areas onthe floor, each rack storage area being arranged to accommodate aplurality of racks (for example arranged in a single row) in which aplurality of rack-mountable electronic components may be housed. Theracks may be already installed in the data centre building or the datacentre building may be provided without racks. The rack storage areasmay include fixings or other means on the floor for facilitating correctpositioning of the racks when installed. Each cold aisle may bepositioned adjacent to a rack storage area. Each hot aisle may bepositioned adjacent to a rack storage area. Cooling air is preferablytransported to the one or more cold aisles under the control of the oneor more air circulation systems.

Thus, in an embodiment of the invention, an over-floor corridor may actas a cooling air duct. By using an over-floor corridor as a coolingduct, high rates of supply of air may be achieved whilst makingefficient use of the space within the volume of the building.

The one or more air circulation systems may comprise one or more fans.Each fan may be sufficiently large to generate an air flow of at least0.5 m³s⁻¹. Each fan is preferably sufficiently large to generate an airflow of at least 1 m³ s⁻¹, and more preferably at least 5 m³ s⁻¹.Together the one or more air circulation systems may have sufficientcapacity to generate an air flow of at least 5 m³ s⁻¹, and morepreferably at least 10 m³ s⁻¹. There may be five or more fans. Forexample, ten or more fans may be provided, such fans collectively beingable to generate an airflow of at least 50 m³ s⁻¹.

The hot or cold aisles may each be positioned between two adjacent rackstorage areas. The hot or cold aisles may extend parallel to a rackstorage area. The present invention also provides certain beneficialaspects which may have advantages in embodiments where there are noreadily discernable hot and/or cold aisles. It will of course beappreciated that the skilled person may also be able, when considering aparticular data centre building without racks installed therein, todiscern which regions of the building would be deemed as the rackstorage areas, as the hot aisles and as the cold aisles. The air supplycorridor may be located wholly outside the rack room. More than one airsupply corridor may be provided.

The air supply corridor may have a height greater than 1.5 m above thefloor, for at least 90% of its length. The air supply corridor may havea large cross-sectional area, namely an area greater than 2 m², andpreferably greater than 3 m². The air supply corridor may have such alarge cross-sectional area for at least 90% of its length. The hot andcold aisles may each have cross-sectional area greater than 2 m², andpossibly greater than 3 m².

In data centres of the prior art it is common to provide under-floor airducts. Certain embodiments of the present invention remove the need forsuch under floor ducts. There is therefore no need to have a high raisedfloor in embodiments of the present invention. The upper surface of thefloor may be less than 500 mm above the base of the building, forexample. Better use may therefore be made of the vertical spaceavailable in a building of a given height. The height of buildings mayfor example be limited if the buildings are assembled off-site andtransported via road or rail networks in a part-assembled or fullyassembled state. Additionally, or alternatively, the under-floor spacemay be utilised for functions other than air-ducts. For example, cablesor other services may be routed under-floor.

Preferably, the data centre building is so arranged that in use airflows along a path from said one or more air circulation systems viasaid corridor to at least one of the cold aisles, such that the air flowis substantially horizontal for the entire path. The path of air-flow ispreferably entirely above floor level. The path of the air-flow may passalong at least part of an access corridor, separate from both (a) theone or more cold aisles and (b) the one or more hot aisles, the accesscorridor facilitating access from outside the building to one of therack storage areas. The one or more air ducts and/or corridors via whichcooling air (whether or not heated by IT equipment in the racks) flowsmay extend in a generally horizontal direction for at least 90% of theirlength and preferably extend only in a generally horizontal directionfor substantially their entire length.

At least one rack room may comprise a plurality of racks. A row of racksmay be provided at each rack storage area. The racks may stand,preferably directly, on the floor. Each rack may be arranged to house aplurality of rack-mountable electronic components, such as ITcomponents. Each rack may be in the form of a rack having a multiplicityof slots arranged in a single column. There may be more than 20 slotsper rack. The slots are preferably arranged such that a single ITcomponent may be mounted in the slot. Such IT components may includeserver blades. The IT components may each be provided within a casing,for example a metal box. The casing may include one or more vents, forexample grilles, at the front and rear of the casing to facilitate theflow of cooling air through the casing to cool the IT component duringuse. There may be one or more fans inside the casing. Preferably, thereare at least 10 racks per rack room, and preferably more than 24 racksper rack room. One or more racks may be housed in a cabinet. There maybe one cabinet per rack. One cabinet may alternatively accommodate aplurality racks. The cabinet preferably has a vent or vents provided onits front face. The cabinet may have a vent or vents provided on itsrear face.

One of the hot or cold aisles may be arranged to act in use as an airduct. For example, the racks, and the adjacent floor and ceiling, maytogether define a volume in which air is entrained, causing a pressuredifference across the rack, which in use allows air to bleed through therack (i.e. to cool electric IT components mounted in the racks). Thevolume defined between adjacent rows of racks may include an inlet, forexample at one end of the rows of racks, and outlets (from theperspective of said “volume”) defined in the racks, but otherwise sealedso as to force air entering the volume to exit only via the racks. (Ofcourse, from the perspective of IT equipment in the racks, the front ofthe racks may be considered as acting as inlets and the back of theracks as outlets.) The bottom of the racks may meet with the floor. Thetops of the racks may meet with the ceiling. The racks may include, orabut, a region of wall that meets with either the floor or ceiling, inthe case where the rack is shorter in height than the floor to ceilingheight.

Cabling may be held above or below the racks in cable ducts that run thelength of the racks. The cable ducts are preferably provided above theracks. Cables may run from such cable ducts to IT equipment in theracks.

The air supply corridor and at least one of (a) the one or more coldaisles and (b) the one or more hot aisles, may conveniently provideaccess to the plurality of rack storage areas.

There may be a plurality of cold aisles. There may be a plurality of hotaisles. The aisles may be substantially straight along their length. Thedata centre building may be so arranged that a plurality of cold aislesare interleaved between a multiplicity of hot aisles. It will beappreciated that a “cold aisle” may be “cold” in the sense that it isupstream of the rack storage area in the direction of flow of coolingair, in use. It will also be appreciated that a “hot aisle” may be “hot”in the sense that it is downstream of the rack storage area in thedirection of flow of air from the racks that has, in use, been heated byIT components in the racks. The hot aisle may be hot in the sense thatthe temperature in the hot aisle is, once a steady state has beenachieved during operation, typically higher then the temperature in thecold aisle.

The data centre building may include an air supply duct for transportingcooling air to the plurality of racks. The air supply duct mayoptionally replace the function of the air supply corridor mentionedabove. At least part of the air supply duct may be defined by means ofthe space between two adjacent racks. For at least 90% of the length ofthe air supply duct, the air supply duct may have a closed cross-sectionhaving an area of at least 2 m². Thus, in an embodiment of theinvention, the racks entrain air-flow and the air duct has a largecross-section. The duct is preferably elongate in geometry. The maximumdimension of the duct (for at least 90% of its length) within the planeof the cross-section of the duct is preferably less than 4 m and morepreferably less than 3 m. Whilst the duct preferably has a largecross-section it is also preferred that the duct is not excessively wideor tall, for example to assist with the entraining of the air flow. Theair supply duct may extend from a source of cooling air, for example oneor more fans, to a plurality of racks. Thus, the air supply duct mayextend from the air circulation systems to the plurality of racks. Atleast part of the air supply duct may be defined by an access corridor.The air supply duct may include a vent controllable to vary the air flowalong the duct. The air supply duct is preferably in fluid communicationwith the space between two different adjacent racks. There may be aplurality of vents, preferably controllable vents. In the case wherethere are two or more cold aisles, there may be a vent provided that isassociated with each cold aisle. The air supply duct (and/or the airsupply corridor) is preferably entirely located above floor-level. Itwill however be appreciated that certain benefits of certain aspects ofthe present invention may be retained in an embodiment of the inventionin which part or all of the air duct is below floor level. For example,below a method of “hot-adding” a rack room to a data centre building isdescribed, wherein such a method may be carried out whether or not theair supply duct is below floor level.

Above reference is made to the “length” of the air duct or the “length”of the air supply corridor. It will be understood that the length inquestion may be the length between the air circulation system(s) and theracks, when installed, or alternatively simply the length upstream ofthe racks.

The data centre building may be so arranged that there is at least oneaisle in the rack room, the aisle being adjacent to a rack storage area,said at least one aisle including a doorway to the aisle, and an accessdoor arrangement. The door arrangement may include a door movablebetween a closed position, closing the doorway, and an open position,allowing personnel access to the aisle. The access door arrangement mayhave a controllable air intake. The air intake may for example comprisea vent. The air intake and/or door may be arranged to move so as toscoop more or less air from an airflow. The air intake may be arrangedto move so as to enlarge or reduce the effective cross-sectional area ofone or more apertures. The controllable air intake may be controllableby moving the door. The door may be moved, whilst still closed, whenvarying the airflow. The door arrangement may include a door and aseparate air-intake. The door may comprise the air intake. The buildingmay be so arranged that, in use, cooling air flows via said doorway intoor from the aisle, for example when the door is closed. The flow of airthrough the door, when in its closed position, is advantageouslycontrollable by means of a controllable vent. Thus, in an embodiment ofthe invention, the access door into the data room has a controllablevent, so that the door has a dual function. It will be appreciated thatthe air flow regime of the building is arranged to function with allsuch doors normally being closed. Thus, the doors are arranged to benormally closed, for example only being opened when personnel access isrequired. In another embodiment of the invention, the door arrangementincludes a door that is movable relative to the wall when the door is inits closed position to allow an air intake to scoop varying amounts ofair from an air supply corridor. In this embodiment, the controllableair intake controls air flow via a different part of the doorarrangement than the part through which personnel can gain access. Thedoor arrangement may be located on the end of a cold aisle. The doorarrangement may be located on the end of a hot aisle, in which case itwill be appreciated that the “cooling air” that passes via the door willtypically have been heated by the rack-mountable electronic components.

As mentioned above, the door may comprise a controllable vent. The ventmay be moveable between an open position thus allowing air to pass viathe vent and a closed position. When in the closed position, airflow viathe vent (controllable air intake) may be restricted (preferablysubstantially prevented). The vent may comprise a row of vertical bladesarranged for rotation about a vertical axis, such that the vent may bemoved between closed and open positions by means of rotation of theblades. The blades may comprise at least one pair of adjacent bladesthat are arranged to rotate simultaneously in opposite directions. Theblades are preferably arranged to rotate together to effect control ofthe flow of air through the vent. There may be two or more motors tomove the blades. There are preferably six or more blades. The bladespreferably extend across more than 50% of the width of the door. Theblades preferably extend across more than 50% of the height of the door.The effective open area when the vent is open may be greater than 1 m².The vent is preferably arranged such that in the event of a failure thevent would fail “open”.

The door arrangement preferably further comprises at least one motor formoving the controllable air intake between an open position thusallowing air to pass via the air intake and a closed position. The atleast one motor is preferably arranged so that the amount of airflowthrough the door may be adjusted between three or more levels. The levelof adjustment possible may be substantially continuous as between thefully closed and fully open positions. The door arrangement may bearranged to receive a control signal for controlling the operation ofthe at least one motor. The control signal is preferably set independence on measured characteristics of the air in or immediatelyoutside the building.

The door arrangement described above may have independent applicationfor use within a building, not necessarily a data centre. Also, it willbe appreciated that the door arrangement could be provided separatelyfrom the data centre building. The present invention thus furtherprovides a door arrangement that is arranged to be fitted within a wallspace, the door arrangement including a door allowing human accesstherethrough and a controllable air intake arranged such that the flowof air through the door, when in its closed position, is controllable bymeans of the controllable air intake. The door arrangement is preferablyarranged to receive a control signal for controlling the operation of amotor provided to move the controllable air intake. Other featuresmentioned above may be incorporated into this aspect of the invention.

The one or more controllable air circulation systems may be arranged tocause circulation of cooling air to rack storage areas under acontrolled pressure regime. An air circulation control unit may beprovided to control such a process. Pressure sensors may for example beprovided to provide a measure of pressure in different regions of thedata centre. The control unit may be arranged to receive signalsrepresentative of the pressure so measured, such signals being used tocontrol the cooling of the data centre. The cooling and/or the pressureregime may of course be adjusted by means of controlling (automatically)the controllable air intake of the access door arrangement mentionedabove. The data centre building may include an airlock room tofacilitate control of the pressure regime. For example, the airlock roommay allow access to a rack room, whilst maintaining the controlledpressure regime. The pressure regime may comprise maintainingdifferential pressures as between the pressure in a cold aisle and thepressure in a hot aisle, so that air flow is encouraged from the coldaisle to the hot aisle. The pressure regime may comprise maintainingdifferential pressures as between the pressure in a hot aisle and adownstream pressure, for example outside the building, to encourageextraction of air away from the hot aisle. The pressure regime maycomprise maintaining differential pressures as between the pressure in acold aisle and an upstream air duct or corridor. The differentialpressure may be required upstream of a cold aisle simply to enabledifferential pressures downstream. The pressure differential between twosuccessive points on the airflow route (for example either side of theracks or either side of an air intake dividing a rack room from anairflow) is preferably greater than 10 Pa, and preferably less than 100Pa.

The airlock room preferably comprises two doors, one door allowing entryinto the airlock room from a location outside of the area of controlledpressure regime and another door allowing entry into the area ofcontrolled pressure regime. Preferably, an electronic control unitprevents the two doors from both being open at the same time duringnormal operation of the data centre. The control unit may for exampleallow the two doors to be open at the same time in the event of anemergency. The building may include a corridor that allows accessbetween the airlock room and another room, for example a rack room. Sucha corridor may also be arranged to allow passage of cooling air, forexample to a rack room.

As mentioned above there may be a cold region, for example a cold aisleand a hot region, for example a hot aisle, the cold region beingseparated from the hot region by a rack. The rack may be a predominantlymetal rack. Preferably, the metal rack includes insulation to reduceconduction and/or convection of heat from the hot region to the coldregion. It has been found that adding a thermal insulating layer toshield the metal framework of the racks can significantly improve thethermal efficiency of the building. This is thought to be as a result ofthe surprisingly high effects of conduction of heat from the hot region,for example a hot aisle to the cold region, for example a cold aisle bymeans of conduction through the metal frame. Thus, in an embodiment ofthe invention, the racks are thermally insulated to prevent, or at leastsignificantly reduce, (reverse) conduction of heat from the hot aisle tothe cold aisle. The metal rack may include uprights, which extend alongthe lateral edges of the rack. The insulation preferably extends tocover the uprights. The rack will of course, in use, include one or morerack-mountable electronic components. In such a case, the insulationpreferably covers substantially the whole of the front of the rack,apart from those regions occupied by the one or more rack-mountableelectronic components. The insulation is preferably arranged so thatslots in the rack for mounting of rack-mountable electronic componentsmay be selectively covered (by insulating material) or exposed to allowinsertion of an IT component (server blade for example). For example,the insulation may comprise a facing that extends across the front ofthe rack, wherein the facing includes a plurality of removable strips.Thus, each strip may be removably mounted to allow (on removal of thestrip) for insertion of a rack-mountable electronic component into therack. The insulation may comprise a portion that extends across at leastone of the two sides of the rack. The rear of the rack may be open. Therack may additionally or alternatively include one or more blankingplates. For example, a blanking plate may be associated with each slotand a removable strip may also be associated with each slot. Suchblanking plates may assist in reducing conduction of heat from the hotaisle to the cold aisle, but may also additionally or alternativelyprovide a better physical seal between the hot and cold aisles andthereby restrict convection of heat from the hot aisle to the coldaisle. Sealing the gaps that might otherwise exist in the area of theracks is important because otherwise cooling air may pass from one sideof the racks to the other via such gaps thereby bypassing therack-mountable electronic components which require cooling. Convectionof heat from the hot aisle to the cold aisle may also be reduced bymeans of removably mounted vertical blanking strips filling the gap thatmight otherwise exist between adjacent racks. Such means may also assistin entraining air-flow through and/or directly over and around therack-mountable electronic components. One or more cables may pass viathe boundary between adjacent racks. As such the racks mayadvantageously include an aperture on each side to allow for passage ofsuch cables. The aperture may be defined simply be means of the spacebetween the front and rear vertical supports on one side of a rack, andthe structure on the side of the rack may for example be substantiallyopen.

The one or more controllable air circulation systems may form part of asingle air cooling system with built in redundancy for ensuringcontinued operation of the data centre building in the event of failureof one of the parts of the air cooling system. The single air coolingsystem may be in the form of a separate module, as described in moredetail below. The single air cooling system may for example comprise amultiplicity of fans including at least one fan more than necessary (atleast N+1 redundancy). The air cooling system may include an activerefrigerant-based cooling unit (possibly one only or possibly two forthe sake of redundancy). The air cooling system may include a mechanicalcooling unit for cooling air before it is used to cool equipment in therack rooms. The mechanical cooling unit may comprise an air conditioningunit, for example having DX refrigeration coils. The mechanical coolingunit may comprise a non-refrigerant based cooling apparatus, for examplea humidification unit, an evaporative cooling unit and/or an adiabaticcooling unit. Redundancy may be provided in the air circulation systemby means of being designed for primary operation withoutrefrigerant-based cooling. For example, the use of ambient air fromoutside the building can be used to cool the racks, provided that thetemperature is below a maximum threshold temperature (for example 37degrees Celsius). Use of ambient air, as the cooling air, can besufficient (for example when utilising embodiments of the presentinvention in which ambient air is treated via a humidity-based coolingunit) for at least 97% of the duration of the operation of the datacentre in certain climates. Thus, the 3% or less of the time whereactive refrigerant-based cooling is additionally required may beconsidered as an exceptional case, such that provision of a doublyredundant refrigerant-based active cooling system is renderedunnecessary. Thus, the data centre building may offer sufficientlyrobust and continuous operation without requiring two independent activerefrigerant-based cooling systems (of the type requiring mechanical DXcooling, condensers, compressors, and the like).

The data centre building is preferably formed from a plurality ofseparate modules. One of the modules may be in the form of a rack roommodule accommodating a rack room. The rack room may include a pluralityof racks in which a plurality of rack-mountable electronic componentsare housed. One of the modules may be in the form of an air circulationmodule. The air circulation module may accommodate one or more aircirculation systems for transporting cooling air to a rack room. The aircirculation module may include a multiplicity (for example four or more)of fans. The air circulation module may include an activerefrigerant-based cooling unit (preferably one only) for cooling airbefore it is used to cool equipment in the rack rooms. The aircirculation module may comprise one or more mechanical cooling units.Each rack room module may include a cooling air duct for transportingcooling air transported from an air circulation module to the rack room.Such a cooling air duct may extend from one side of the rack room moduleto an opposite side. One of the modules may be in the form of a servicesplant module. The services plant module may comprise power plantequipment. The services plant module may comprise fire suppressionequipment. The services plant module may comprise control equipment forcontrolling cooling and powering of IT equipment in one or more rackrooms. The power plant equipment (in the services plant module) mayinclude an uninterruptible power supply (UPS), for example including abattery back-up unit. The power plant equipment may include switchgearequipment. The power plant equipment may include electrical distributionequipment. One of the modules may be in the form of a personnel module.The personnel module may be arranged to provide secure access to thedata centre building. The personnel module may include office space. Thepersonnel module may include an airlock room. The personnel module mayinclude a door providing access to one or more data rooms. One module,not itself being a rack room, may define a cold aisle, or morepreferably a hot aisle, adjacent to a rack storage area in a rack room.In an embodiment described below, the services plant module (comprisingthe power plant equipment) includes a hot aisle, such that a corridor ofthe services plant module acts, in use, as an exhaust duct.

The data centre building preferably comprises at least one rack roommodule, at least one air circulation module, and at least one servicesplant module. According to certain embodiments of the invention, one aircirculation module serves many rack room modules. Providing a datacentre building in which a single air circulation module is able toserve more than one rack room modules enables a data centre building tobe constructed having one or relatively few rack room modules and thenadding further rack room modules as demand for IT capacity grows,without requiring the addition of an extra air circulation module. Itwill therefore be appreciated that there may be advantages to providinga data centre building having one or more rack room modules, and one ormore air circulation modules, wherein all of the one or more aircirculation modules have the capacity to cool more than all of the oneor more rack room modules. For example, the one or more air circulationmodules may have the capacity to cool at least twice as many rack roommodules as are provided. The one or more air circulation modules mayhave more than three times the required capacity. For example, eachsingle rack room may have a cooling requirement of at least 10 kW, or atleast 50 kW. Some data centre designs may have rack rooms each having acooling requirement of greater than 150 kW. A single air circulationmodule may have a cooling capacity of more than 200 kW, and possiblymore than 300 kW, thus allowing for future expansion.

Each module may have a similar construction. Each module may comprise aframe structure having a rigid base from which there extends amultiplicity of vertical structural support columns. The frame structuremay include two or more beams at the top of the frame each extendingbetween a pair of the vertical support columns. The base may comprise asteel frame. The steel frame may be formed by means of a plurality ofI-beams. The base may be formed from concrete supported on a steelframework or sheeting. The module may comprise a roof section. The basemay comprise a timber floor fixed onto a frame. The base may be formedfrom board material supported on joists. The joists may be metal. Eachmodule preferably has a length greater than 10 meters. Each modulepreferably has a length less than 20 meters. Each module preferably hasa height greater than 2 meters. Each module preferably has a height lessthan 4.2 meters. Each module preferably has a width greater than 2.5meters. Each module preferably has a width less than 5 meters. A modulemay include a wall extending upwards from at least one edge of the base.A module may have a base having an edge extending between two corners ofthe base, such that the edge (or at least a part of it) is notassociated with a wall, thus defining a substantially open face of themodule. The module may have an open face to cooperate with acorresponding open face of an adjacent module in a building, so that anopen space (for example as part of a room or corridor of the building)is defined partly by one module and partly by an adjacent module. Itwill be appreciated that the open face may extend only part of the wayalong the edge of the base, there being a wall along the remainingpart(s) of the edge. Each module is preferably shaped so as to besuitable for transportation by road. Each module preferably includesstructure configured to allow the module to be lifted by, for example, afork-lift.

When the modules are assembled to form the data centre building, theremay be a gap between adjacent modules. The gap is preferably between 2.5mm and 50 mm, preferably between 5 mm and 20 mm. The gap betweenadjacent modules is preferably filled with one or more sealing strips.The sealing strip may be metal.

The present invention also provides a method of cooling electronicequipment in a data centre building. The method may comprise a step ofproviding and then operating a data centre building according to thepresent invention as described or claimed herein. The method may includea step of cooling racks of items of electronic equipment by operatingone or more air circulation devices to transport air above the floor viaat least one access corridor, providing access to the racks. The methodmay include a step of removing air from the racks. The method may causethe removed air to be exhausted directly to the exterior of thebuilding. The method may cause the removed air to pass via an accesscorridor. The access corridor preferably extends from a location outsideof the rack room to a location inside the rack room. The access corridormay comprise a door. The access corridor need not be straight.

The air circulation devices may use one or more fans to push air throughthe building. The one or more exhausts may therefore be passiveexhausts, in that the exhausts do not themselves assist extraction ofair from the building. The passive exhausts may include one or morecontrollable vents.

The method may include a step of cooling racks of items of electronicequipment by operating one or more air circulation devices to transportair from outside the building at ambient air temperature to the racks,preferably without utilising refrigerant-based active cooling. The airmay then be removed from the racks and exhausted to outside the buildingvia at least one air exhaust. The one or more air circulation devicesmay be provided upstream of the racks. The one or more air circulationdevices preferably provide a sufficient pressure differential, ascompared to the air pressure immediately outside the building, to beable independently to cause air to be exhausted out of said at least oneexhaust at a rate of at least 10 m³ s⁻¹ per rack room (or optionally atleast 8 m³ s⁻¹ per rack room, or optionally at least 5 m³ s⁻¹ per rackroom). Such rates might represent the higher end of the likely range ofoperational air exhaust rates. The data centre building may be arrangedto operate at low IT demand levels with exhaust rates of the order ofonly 0.3 m³ s⁻¹ per rack room. In the case where there are for example,three or more (or optionally five or more) rack rooms in a building, ora floor thereof, air may be exhausted at a rate of at least 50 m³ s⁻¹from the building (or floor of the building, as the case may be), whenoperating at high demand for example. Alternatively or additionally, airmay be exhausted out of said at least one exhaust at a rate of at least0.4 m³ s⁻¹ per rack. If there are 24 racks in a rack room, such a ratewould be equivalent to about 10 m³ s⁻¹ per rack room. Alternatively oradditionally, air may be exhausted out of said at least one exhaust at arate of at least 0.002 m³ s⁻¹ per slot in the racks in the room. Ifthere are 40 racks in a rack room and 40 slots per rack, such a ratewould be equivalent to about 3.2 m³ s⁻¹ per rack room. Alternatively oradditionally, air may be exhausted out of said at least one exhaust at arate of at least 0.005 m³ s⁻¹ per rack slot, preferably at a rate of atleast 0.008 m³ s⁻¹ per rack slot. At low demand, the air may beexhausted out of said at least one exhaust at a rate of as little as0.00024 m³ s⁻¹ per rack slot. If there are 24 racks in a rack room and40 slots per rack (of which at any given time 10 or more are each closedover by a blanking strip thereby restricting or preventing the flow ofair therethrough), such a rate may be equivalent to less than 0.2 m³ s⁻¹per rack room. Air may be exhausted out of said at least one exhaust ata rate of at least 0.01 m³ s⁻¹ per rack slot, or possibly at least 0.15m³ s⁻¹ per rack slot (such rates again representing the higher end ofthe range of likely operational exhaust rates). Thus, in an embodimentof the invention, a sufficiently large volume of air per second is usedto effect “ambient air” cooling of the IT equipment in the data room.There may therefore be less of a need for use of refrigerant-basedactive cooling. In certain embodiments of the invention, there is forexample no need for CRAC units to be provided. This means of cooling maybe used even when the ambient air temperature outside is higher than 20degrees Celsius. Preferably, the method includes a step of operating thedata centre and cooling it by means of airflows where the rate ofexhaust is greater than 5 m³ s⁻¹ per rack room and also a step,performed at a different time, of operating the data centre and coolingit by means of airflows where the rate of exhaust is less than 1 m³ s⁻¹per rack room.

There may be fewer exhausts than there are rack rooms. There may be atleast 10 racks per room, preferably more than 20 racks per room. Eachbuilding may include more than two rack rooms. Preferably, however,there are fewer than ten data rooms/rack rooms per floor of thebuilding. Each rack may have more than 10 slots for insertion ofseparate IT equipment units. Each rack may have more than twenty suchslots. Thus, each rack room may, when operating at full capacity,accommodate over 500 separate equipment units, and possibly more than1,000.

The method may extract heat at a rate of at least 5 kw per rack roommodule, or optionally at a rate of at least 10 kw per rack room module.When IT demand is high, there may be a need for higher heat extractionrates. The method may extract heat at a rate of at least 50 kw per rackroom module, and possibly at a rate of at least 80 kw per rack roommodule. Such heat extraction rates may be achieved solely with ambientair cooling.

The method may additionally include a step of detecting fire or smoke.In the event that fire or smoke is detected, the method may include astep of ceasing transport of air from outside the building. Such a stepmay be conducted under the control of a fire suppression control unit.The method may also include a step of closing the one or more airexhausts. The method may include a step, in the event that fire or smokeis detected, of causing cooling air to be re-circulated. For example,the items of electronic equipment may be cooled by operating the one ormore air circulation devices to transport air from within the building,to the racks and then from the racks back to the air circulationdevices, with an optional step of cooling the air (for example by meansof mechanical cooling equipment). Once air is being re-circulated withinthe building, a fire suppression control unit may then be able todiscern whether the fire/smoke previously detected was from outside thebuilding or inside the building. If fire or smoke continues to bedetected, then appropriate action may be taken. For example, firesuppression gas may be released into the data centre building.Embodiments of the present invention enable rapid deployment of firesuppression gas throughout the data centre building as a result of thelarge volume of air/gas that is able to flow through the building persecond.

The present invention yet further provides a method of building a datacentre building. The data centre building so built may be in the form ofa data centre building according to the present invention as describedor claimed herein. The method of building the data centre building maycomprise a step of extending an existing modular data centre building,in which there is provided at least one rack room module accommodating arack room having a plurality of racks in which a plurality ofrack-mountable electronic components are housed. There may be an aircirculation module accommodating one or more air circulation systems fortransporting cooling air to said at least one rack room in each rackroom module. Each rack room module may include a cooling air duct fortransporting such cooling air from the air circulation module to therack room, the cooling air duct extending from one side of the rack roommodule to an opposite side. The step of extending an existing modulardata centre building is advantageously conducted whilst the plurality ofrack-mountable electronic components in each rack room of the existingbuilding are operated and cooled by means of air from said at least oneair circulation module. The method may include a step of adding afurther (new) rack room module accommodating a rack room and having acooling air duct extending from one side of the rack room module to anopposite side, such that an end of the cooling air duct on one side ofthe further (new) rack room module is aligned with an end of the coolingair duct on one side of a rack room module of the existing modular datacentre building. The method may then include a step of connecting thecooling air duct of the further (new) rack room module with the coolingair duct of the rack room module of the existing modular data centrebuilding. The method may include a step of removing an end portion ofthe building (for example a further module, optionally in the form of apersonnel module) from the end of the existing data centre building toexpose the side of the rack room module at the end of the existingbuilding to which the extension is to be added. The method may include astep of blocking off an end of the cooling air duct of the rack roommodule of the existing modular data centre building before such an endportion of the building is removed. By utilising a modular buildingtechnique a “hot add” (i.e. allowing continuity of operation of the ITequipment in the data centre building) of an extra rack room may beachieved in a matter of days (for example less than 48 hours), ascompared to previous timescales of the order of weeks.

The invention also provides a rack room building module for building adata centre installation, wherein the module comprises:

a base for supporting a floor,

a plurality of racks for housing a plurality of rack-mountableelectronic components, and

an above-floor cooling air duct extending from one side of the rack roommodule

to an opposite side.

In an embodiment of the invention, the rack room building modulecomprises a steel frame having the dimensions of an ISO shippingcontainer. It may be constructed so as to be suitable for transportingas a shipping container. Advantageously, this embodiment of theinvention may be used both in easily accessible areas such as citycentres and in remote areas.

It will of course be appreciated that features described in relation toone aspect of the present invention may be incorporated into otheraspects of the present invention. For example, the method of theinvention may incorporate any of the features described with referenceto the apparatus of the invention and vice versa.

The present invention further provides a method of constructing a datacentre in a building. The method may include the steps of:

-   -   (a) providing a space within the building;    -   (b) providing at least one hole in an external wall of the        building through which outside air may enter the space and/or        inside air may leave the space;    -   (c) providing at least one partition to be installed in the        space;    -   (d) installing the at least one partition in the space such that        the partition(s) define:        -   at least one rack room having a floor and a plurality of            rack storage areas on the floor, each rack storage area            being arranged to accommodate a plurality of racks in which            a plurality of rack-mountable electronic components may be            housed;        -   one or more cold aisles in the rack room, each cold aisle            being adjacent to a rack storage area,        -   one or more hot aisles in the rack room, each hot aisle            being adjacent to a rack storage area, and;        -   an air supply corridor for transporting, under the control            of the one or more air circulation systems, cooling air,            above the floor, to the one or more cold aisles, the air            supply corridor having a height greater than 1.5 m above the            floor;    -   (e) installing in the space one or more controllable air        circulation systems.

Advantageously, the method provides a data centre that can be used inlocations where the construction of a new building may not be possibleor desirable, such as in city centres. The method may also be used by anorganisation with an existing data centre or data room to easily upgradethe existing data centre or data room to use the present invention,thereby improving its efficiency. Alternatively, it may be used in abuilding that has been purpose-built to accommodate a data centreconstructed according to the method.

The present invention also provides a kit of parts for constructing adata centre in a space within a building, wherein the kit includes atleast one partition arranged for installation in the space such that thepartition(s) and the space cooperate so as to define:

at least one rack room having a floor and a plurality of rack storageareas on the floor, each rack storage area being arranged to accommodatea plurality of racks in which a plurality of rack-mountable electroniccomponents may be housed;

one or more cold aisles in the rack room, each cold aisle being adjacentto a rack storage area,

one or more hot aisles in the rack room, each hot aisle being adjacentto a rack storage area, and;

an air supply corridor for transporting, under the control of the one ormore air circulation systems, cooling air, above the floor, to the oneor more cold aisles, the air supply corridor having a height greaterthan 1.5 m above the floor.

DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying schematic drawings, ofwhich:

FIG. 1 shows a prior art rack room;

FIG. 2 is a very schematic drawing showing a data centre buildingaccording to an embodiment of the invention;

FIG. 3 shows a data centre building according to another embodiment ofthe present invention;

FIG. 4 is a partial plan view of a data centre building according to yetanother embodiment, including schematic shading of hot and cold areas;

FIG. 5 shows the air optimisation module of the data centre building ofFIG. 3;

FIG. 6 shows the plant room module of the data centre building of FIG.3;

FIG. 7 shows the rack room module of the data centre building of FIG. 3;

FIG. 8 shows the entry module of the data centre building of FIG. 3;

FIGS. 9-12 show how the data centre building of FIG. 3 can be enlargedby adding further rack room modules;

FIG. 13 shows a multi-story data centre building;

FIG. 14 is a plan view of the data centre building of FIG. 4, operatingwhen the ambient air is at a temperature of less than 18° C.;

FIG. 15 is a partial plan view of the data centre building of FIG. 4,operating when the ambient air is between 18° C. and 24° C.;

FIG. 16 is a partial plan view of the data centre building of FIG. 4,operating when the ambient air is between 24° C. and 37° C.;

FIG. 17 is a partial plan view of the data centre building of FIG. 4,operating when the ambient air is at a temperature greater than 37° C.;

FIG. 18 is a perspective view of a rack row for use in embodiments ofthe present invention;

FIGS. 19a to 19d show a rack room door with variable air flow intakeaccording to a yet further embodiment of the invention;

FIG. 20 shows a rack room door with variable air flow intake accordingto another embodiment of the invention.

FIG. 21 shows a perspective view of a data centre building according toyet another embodiment of the invention;

FIG. 22 shows an exploded perspective view of the data centre buildingof FIG. 21;

FIG. 23 shows a plan view of a floor of a building including three datacentres according to a further embodiment of the invention; and

FIG. 24 shows a partial perspective view of a partially constructed datacentre according to the embodiment of FIG. 23.

DETAILED DESCRIPTION

FIG. 2 shows a data centre building 10. The building 10 is rectangularwith external walls 12. The building is divided into front and rearsections by an internal dividing wall 12 a, located approximately onethird of the length of the building from the rear external wall.

The rear section (on the left in FIG. 2) defines an air optimisationroom 11, which provides a system of circulating cooling air in thebuilding 10. Ambient air (represented by the light arrow 18) can enterthe air optimisation room 11 through an ambient air intake 13 in therear external wall. Ambient air 18 can be treated/cooled in the airoptimiser room and this air 18 a is then used for cooling. If theambient air outside the building 10 is sufficiently cool, the ambientair may be used as cooling air, without requiring any activerefrigerant-based cooling by the air optimisation room 11. Cooling air18 a passes into the front section of the building 10 through acontrollable vent 17 in the internal dividing wall 12 a.

The front section (on the right in FIG. 2) of the building 10 defines arack room 19. The rack room 19 houses two rows of racks 14. The racks 14extend away from the internal dividing wall 12 a, towards the front ofthe building. Each rack row extends approximately out to two thirds ofthe length of the front section of the building. Although only shownschematically in FIG. 2, there are 20 racks in each row, each rackhousing up to 40 items of IT equipment (typically server blades). Theremay therefore be as many as 1,600 items of IT equipment in the racks. Ablanking panel 14 a extends between the front ends of the two rows ofracks, thereby defining a cold region 19 a between the internal dividingwall 12 a, the two racks 14 and the blanking panel 14 a.

A hot region 19 b is defined on the other side of the racks 14 and theblanking panel 14 a. Air can escape from the hot region 19 b though ahot air exit 15 in the front external wall of the building.

In use, ambient air 18 enters the air optimisation room 11 through theambient air intake 13. The ambient air 18 is cooled/treated as necessaryin the air optimisation room 11 resulting in cooling air 18 a, whichenters the rack room 19, into the cold region 19 a, via the vent 17. Thecooling air 18 a moves over the racks 14 in the rack room 19 to reachthe hot region 19 b and in the process cools the racks 14. The resultinghot air (indicated by dark arrows 16) coming off the racks 14 thenleaves the rack room through the hot air exit 15. It will of course beappreciated that the hot air 16 is simply the result of the cooling air18 a having been heated by the equipment in the racks 14 and isotherwise essentially the same air. As such the operation may beconsidered as involving the flow of cooling air into the rack room 19,the flow of cooling air via the racks 14 and then the flow of coolingair (then heated by the racks such that the “cooling air” may then haveless, if any, ability to cool) out of the rack room. As such “hot air”or “exhaust air” can be considered as heated or used “cooling air”. Inthe Figures air upstream of the racks is indicated by light arrows anddownstream or exhaust air is indicated by dark arrows.

The volume of air flow through the building may, during certainconditions for example when outside temperature is relatively highand/or IT loads are relatively high, be at least 12 m³ s⁻¹. The airoptimiser module has the capacity to generate air flow through thebuilding at a rate as high as at least 40 m³ s⁻¹ (i.e. more than about 1m³ s⁻¹ per rack and about 0.025 m³ s⁻¹ per rack slot, assuming thatsubstantially all air flowing through the building passes via a rackslot). The volume of air flow through the building may during otheroccasions be about 0.3 m³ s⁻¹, during certain conditions. Such a rate ofsupply of air may still be sufficient to cool the IT equipment in thesingle rack room of the building by means of ambient air cooling alonefor ambient air temperatures of up to 24 degrees Celsius.

FIG. 3 shows a rectangular data centre building 100 with external walls110 and a flat roof of a further embodiment.

At the front of the building 100 is a hole in the external wall definingan entrance 111. On a right side of the building, towards the rear is asecond hole in the external wall defining a fire exit 112. Also on theright side of the building, behind the fire exit 112 is a hole definingan ambient air intake hole 113 (not visible). In front of the fire exit112 but also on the right side of the building is a hole defining a hotair outlet hole 114.

The data centre building 100 is made up of four rectangular modules thatare placed side to side so that the long sides of the rectangularmodules are adjacent each other. The ends of the rectangular modulesform the external side walls of the building. The external walls of themodules are formed from steel frames that are welded and bolted.

The floor of the modules is formed from steel frames and joists. Thefloor panels additionally have timber floorboards. The roof isconstructed from a suitable weatherproof panel system and watertightmembrane, including falls to one side of the roof and external drainagecollection. The wall panels of the modules are formed from highlyinsulated steel panels, with a fire resistance of at least one hour. Inaddition, the wall and roof panels may also be constructed with magneticshielding, RF or X-ray protection. The internal finish of the walls andceiling is a plastic coated galvanised steel finish.

The modules are connected to each other by using modular wiring systemsor quick disconnects on mechanical pipework. Hence, the modules can beeasily connected and disconnected from each other.

In the embodiment shown in FIG. 3, there is an air optimisation module120 located at the rear of the building 100, a plant room module 130located in front of the air optimisation module 120, a rack room module140 located in front of the plant room module 130 and a personnelmodule, here in the form of an entry module 150, located in front of therack room module 140, at the front of the building 100.

The air optimisation module 120, shown most clearly in FIG. 5, includesthe rear external wall of the building 100 and the rearmost parts of theleft and right side walls of the building.

The air optimisation module 120 contains an air optimisation unit 122located at the rear, right corner of the building. The air optimisationunit 122 is located adjacent the external right side wall of thebuilding 100 so that an ambient air intake grille 121 (not visible) onone end of the unit 122 lines up with the ambient air intake hole 113.The ambient air intake grille 121 includes vents that are controllableso that the amount of air entering the air optimisation unit 122 throughgrille 121 can be controlled.

The air optimisation unit 122 also has a second air intake in the formof a return air grille 125. The return air grille 125 is located at theright, front end of the optimisation unit 122, near the end wallincluding the ambient air intake grille 121. The return air grille 125includes vents that are controllable so that the amount of air enteringthe air optimisation unit 122 through grille 125 can be controlled.

The air optimisation unit 122 contains various air treatment apparatus,including banks of fans, air filters, humidification apparatus and anactive DX cooling system. The DX cooling system includes soft copperrefrigeration pipework. The humidification apparatus is used to provideadiabatic cooling during use. The air optimisation unit 122 alsocontains an air mixing box (not shown) for mixing the air from returnair grille 125 and ambient air intake grille 121. The unit 122 alsocontains sound attenuation apparatus.

To the left side of the air optimisation unit 122 is an air supplycorridor 123. The air supply corridor 123 runs from the rear externalwall, and along and in between the left side of the air optimisationunit 122 and the left external side wall. A curved wall 124 is locatedin the rear, left corner of the building to help direct air from the airoptimisation unit 122 along the corridor 123.

The floor of the air optimisation unit 122 is a non-slip safety floor.

The plant room module 130, shown most clearly in FIG. 6, includes twoparts of the two external side walls of the building.

The plant room module 130 contains a rectangular plant room 133 definedby plant room walls 134. The plant room 133 is located centrally along arear side of the plant room module 130. When the air optimisation module120 and the plant room module 130 are joined, the plant room 133 sitsagainst the front side of the air optimisation module 120 and the leftend of the plant room 133 lines up with the left end of the airoptimisation unit 122.

At the left, front end of the plant room 133, plant room wall 134 isextended to the front side of the plant room module 130. Hence, apassageway running along and in between the left external side wall ofthe building and the plant room wall 134 is defined. This passagewayruns along the width of the plant room module 130 and is closed off fromthe plant room 133 and the rest of the plant room module 130 by theplant room walls 134. The passageway joins up with and forms part of theair supply corridor 123.

To the right side of the plant room module 130 is a hot air corridor 132running along the width of the plant room module 130 and along theexternal side wall of the building containing the fire exit 112. Theplant room module 130 contains a fire exit door 135 over the fire exit112. When the air optimisation module 120 and plant room module 130 arejoined together, the hot air corridor lines up with the return airgrille 125.

The hot air corridor 132 also extends around the front of the plant room133, in between the front plant room wall 134 and the front of the plantroom module 130. This corridor extends up to the right side of theextended plant room wall 134. This allows air from the rack room module140 (located in front of the plant room module 130) to enter the hot aircorridor 132.

On the left end wall of the plant room 133 is a plant room access door131. The door 131 allows access to the plant room 133 from the hot aircorridor 132.

The plant room 133 contains various apparatus, including firesuppression gas discharge canisters 136 and associated manifold andvalves, a power metering panel 137 a for monitoring the power consumedby each rack in the rack room module 140, a dual electrical distributionpanel 138, an uninterruptible power supply 139 a and back-up batteries139 b. These apparatus are mounted on the internal sides of the plantroom walls 134.

The plant room 133 also contains a process control panel 137 b,including a VESDA (Very Early Warning Smoke Detection Apparatus) firedetection monitoring panel, mounted on an internal side of the plantroom walls 134. The process control panel 137 b receives data fromvarious sensors including sensors in the rack room module 140 and anoutside ambient air temperature sensor. This outside ambient airtemperature sensor may be placed outside the building 100 or just insidethe building 100, near the ambient air intake grille 121. It uses thisinformation to control the fans, humidification apparatus, coolingsystem and controllable vents in the building in order to achieveeffective cooling of the racks in the rack room module 140.

The fire suppression gas discharge canisters 136 are connected to theair optimisation unit 122 so that in the event of a fire (when the VESDAmonitoring panel is triggered), gas from the canisters 136 can bedischarged through the air optimisation unit 122 into air supplycorridor 123.

The uninterruptible power supply 139 a and back-up batteries 139 b aredesigned to provide 10 minutes of power in the event of failure of anexternal power supply. The batteries are provided with their owndedicated cooling system.

The floor of the plant room 133 is a non-slip safety floor.

The rack room module 140, shown most clearly in FIG. 7, includes partsof the external side walls of the building.

The rack room module 140 contains two elongate rectangular rack storageareas, the areas being parallel to each other. The areas are togetherpositioned centrally along a rear side of the rack room module 140. Atthe left end of the rack storage areas is an internal wall 141 runningalong the width of the rack room module 140. When the plant room module130 and the rack room module 140 are joined, the rack storage areas sitagainst the plant room module 130 and the internal wall 141 lines upwith the left end of the air optimisation unit 122 and left wall 134 ofthe plant room 133.

Hence, a passageway running along and in between the left external sidewall of the building and the internal wall 141 is defined. Thispassageway runs along the width of the rack room module 140 and isclosed off from the rack room area and the rest of the rack room module140 by the internal wall 141. The passageway joins up with and formspart of the air supply corridor 123.

Each rack storage area is effectively defined by a single row of racks143 running lengthways along the rack room module 140, i.e. widthwaysacross the building, from the internal wall 141 to the right end of therack room area. The two rows of racks 143 are separated by a cold aisle144.

At the right end of the rack room area, spanning across the ends of bothrack rows, is a cold aisle blanking panel 147 designed to close off thecold aisle 144 at the right end. At the top of both rows of racks 143are over-rack blanking plates 148 designed to stop cold air travellingover the racks 143 between the top of the racks and the ceiling of therack room module 140. Hence, air can only leave the cold aisle 144through the racks 143. There is no personnel access possible from thecold aisle 144 directly to the other side of the racks 143.

Air from the supply air corridor 123 can enter the cold aisle 144through cooling air intake grille 142, located on the internal wall 141in between the rows of racks 143. The grille 142 includes vents that arecontrollable by the process control panel 137 b so that a desired airpressure regime can be achieved. The cooling air intake grille 142 ispart of a securable door that can be opened and closed to allowpersonnel access from the air supply corridor 123 to the cold aisle 144of the rack room module 140. The cooling air intake grille door 142 ismade from aluminium and/or steel.

The rearmost row of racks 143 is located adjacent the passageway in theplant room module 130 that joins up with the hot air corridor 132.Hence, hot air coming from the rearmost rack 143 is directed to the hotair corridor 132 via this passageway. Hence, the passageway is definedas a hot aisle 145.

Around the right end and along the front side of the front rack is apassageway that joins up with and forms part of the hot air corridor 132running along the right side of the building 100. Hence, hot air comingfrom the other (foremost) rack 143 is directed to the hot air corridor132 via this passageway. Hence, the passageway is also defined as a hotaisle 145.

On the right end wall of the rack room module 140 is a hot air outletgrille 146 corresponding to the hot air outlet hole 114. The grille 146has vents that are controllable by the process control panel 137 b sothat the amount of hot air 16 that is exhausted from the building 100through hot air outlet grill 146 can be controlled.

FIG. 18 shows a row of racks 143 in more detail. The rack frames 143 aare made of metal. Each rack is an open fronted 42 u standarduniversally compatible server rack. The racks are joined together inrows by filler pieces 143 c. The filler pieces can be a plain infillpanel, a vented infill panel (including a mesh panel on the fillerpiece), a power distribution support infill panel or a cable managementinfill panel. It is preferred for the filler pieces 143 c to be in theform of vertically extending blanking strips that seal the racks andthereby restrict undesirable heat convection. Cables are run verticallyto the top of the racks through the cable management panels and guidedthrough cable trays (not shown) at the top of the racks. Cables can thenbe run down one side of the row of racks 143 in cable trough 143 d.Hence, the cable is kept out of the air flow and this improvesefficiency. A gasket seal 143 e is provided around the top of the racks143 to provide a seal against air flow.

Each rack is fitted with a “42u” insulation strip. The insulation stripis made up of individual blanking strips 143 b that can be removed fromthe racks. Each individual blanking strip 143 b corresponds in height tothe height of each unit space on the rack. Hence, individual blankingstrips 143 b can be placed on the racks to cover any area not occupiedby electronic components in the racks. The strips 143 b can be removedto allow additional electrical components to be inserted in the racks143. The strips 143 b reduce the conduction of heat from the hot aisles145 to the cold aisle 144. Insulation material is also placed on theover-rack blanking plates 148 and cold aisle blanking panel 147 (notshown in FIG. 18). Thus, the metal rack includes a thermally insulatingbarrier that reduces flow of heat from the hot aisle to the cold aislevia heat conduction across the metal rack.

A floor 149 of the rack room module 140 has an anti-static vinylcovering.

The rack room module 140 also contains sensors for measuring the airtemperature, humidity level, pressure and air flow. These sensors areconnected to the process control panel 137 b in the plant room 133.

The entry module 150, shown most clearly in FIG. 8, includes the frontexternal wall and the foremost parts of the external side walls of thebuilding.

The entry module 150 has an entry portal 151 located adjacent theentrance 111 to the building 100. The entry portal 151 is asemi-circular door surrounding the entrance 111 to the building. Hence,upon entering the building, personnel pass through the entrance door 111into a semi-circular space defined by the entry portal 151 and thenthrough the semi-circular entry portal 151 itself. The entry module 150also has a security/reception area 152, located to the left and to therear of the entry portal 151.

On the right side of the entry module, in the front right corner of thebuilding 100, is a storage and IT staging room 153, accessed through adoor 154. To the rear of the storage and IT staging room 153, located inthe right, rear corner of the entry module 150, is an air lock room 155.The air lock room 155 is accessed from the security/reception area 152through an air lock access door 156. An air supply corridor access door157, adjacent the right side wall of the building, provides access fromthe air lock room 155 to the air supply corridor 123 of the rack roommodule 140.

The air supply corridor access door 157 can only be opened when the airlock access door 156 is closed. Similarly, the air lock access door 156can only be opened when the air supply corridor access door 157 isclosed. Hence, loss of air pressure of the air supply corridor can bereduced, while still allowing personnel access to the air supplycorridor 123 and cold aisle 144, through the door of the cooling airintake grille 142.

On the rear side of the entry module 150 are two central windows 158allowing personnel in the entry module 150 to see into the rack roommodule 140.

In the right, rear corner of the entry module 150 is a hot air corridoraccess door 159. This door 159 links up to the hot air corridor 132 ofthe rack room module 140 and hence allows personnel access to the hotair corridor 132, the rear of the racks 143 facing the hot aisles 145and the plant room 133, through plant room access door 131.

The floor of the entry module 150 is a non-slip safety floor.

The plant room 133 and the entry module 150 contain their own heatingand ventilation system that is not connected to the supply of air fromthe air optimisation unit 122. The heating system includes an electricpanel heater with an integral thermostat.

All external doors of the building 100 (i.e. entrance 111 and fire exitdoor 135) are made from aluminium or steel. The doors can contain doubleglazed window panels.

FIG. 4 shows a data centre building 100, similar to that shown in FIG.3. However, the building of FIG. 4 has three rack room modules 140. Eachrack room module 140 is identical. Hence, a building 100 is providedthat can accommodate more racks 143.

Cooling air 18 a from the air supply corridor 123 can enter the coldaisle 144 of each rack room module 140 through the controlled vents ofthe cooling air intake grilles 142. The hot air 16 from the racks 143can leave the rack room modules 140 through hot aisles 145 in betweenthe racks 143. The hot air 16 then reaches the hot air corridor 132, asbefore.

FIG. 9 shows a data centre building with an air optimisation module 120,a plant room module 130, an entry module 150 and two rack room modules140.

FIG. 10 shows that the entry module 150 of the building 100 of FIG. 9can be removed to leave the front of the second rack room module 140exposed. A blocking panel 141 a is placed over then front end of the airsupply corridor 123 to reduce loss of air supply pressure.

FIG. 11 shows that three (or any number) of additional rack room modules140 can be placed next to the existing rack room modules 140 such thatthe internal walls 141 line up to create a lengthened air supplycorridor 123. Hence, the building of FIG. 11 contains an airoptimisation module 120, a plant room module 130 and five connected rackroom modules 140.

FIG. 12 shows that the entry module 150 removed from the building 100 ofFIG. 9 can be replaced next to the foremost rack room module 140 of FIG.11. Hence, the building of FIG. 9 can be expanded from having two rackroom modules 140 to having five rack room modules 140.

As many rack room modules 140 as desired can be added, as long as thecapacity of the air optimisation unit 122 is sufficient to cope with thecooling requirements of all the rack room modules 140.

The expansion of data centre buildings 100 can be conducted whilst theelectronic components in each rack 143 of the existing rack room modules140 are operated and cooled by cooling air 18 a from the air supplycorridor 123. Such a process is referred to elsewhere in this documentas a “hot add” process.

FIG. 13 shows a multi-story data centre building 100. The building 100has three stories stacked on top of each other. Each story is made up ofan air optimisation module 120, a plant room module 130, three rack roommodules 140 and an entry module 150. The particular type of modularconstruction employed by this embodiment lends itself to a fullyscalable, and very flexible, data centre construction method.

In addition, each story includes a stair module 160 placed in front ofthe entry module 150, on the right hand side. Each stair module 160 isrectangular with a height identical to the entry module 150 and the restof the modules, a width similar to the entry module 150 and a length ofabout half that of the entry module 150.

Each stair module 160 has an exit door 163 (visible for third storyonly) on the left rear corner of the module 160 such that the exit door163 lines up with and allows access to the entry portal 151 of the entrymodule 150. Hence, the exit door 163 of each stair module 160 allowsaccess to the entry module 150 on the respective level.

Each stair module 160 also contains a set of stairs 162 extending fromthe bottom of the stair module 160 to the top of the stair module 160.Hence the stairs 162 allow personnel to move up to the entry module 150above.

Of course, for the uppermost (third) story, there is no level above andso the stairs 162 do not lead up to a next level.

The lowermost (first) story stair module 160 also has an entry door 161located on the left side of the front wall of the stair module 160 toallow personnel access to the building 100.

Alternatively, any or all of the above described embodiments, may notinclude an entry module 150. Instead, the front side of the foremostrack room module 140 is enclosed by an external front wall. The externalfront wall should include an air supply corridor access door on the lefthand side to allow access to the air supply corridor 123 and a hot aircorridor access door on the right hand side to allow access to the hotair corridor 132.

In use, the data centre building 100 of any of FIG. 3, 4, 9, 12 or 13operates to cool the racks 143 in the rack room module(s) 140 bygenerating a sufficient quantity, velocity and pressure of cooling air18 a in the air optimisation unit 122. The air optimisation unit 122also filters the air using air filters and performshumidification/de-humidification on the air, as necessary.

The cooling air 18 a is pushed out of the air optimisation unit 122,directed by the curved wall 124 and moves along the air supply corridor123. The vents in the cooling air intake grille(s) 142 are controlled soas to ensure appropriate distribution of the cooling air 18 a in thecold aisle(s) 144 of the rack room module(s) 140 in dependence on thecooling requirements of the IT equipment in the racks associated witheach cold aisle (which may for example be measured by temperaturesensors at the rear of the racks). The cooling air 18 a is drawn acrossthe racks in the rack room module(s) 140 by the integral fans in theelectrical components in the racks and cools the electrical components.

The resulting hot air 16 moves through the hot aisles 145 in the rackroom module(s) 140 and plant room module 130 to the hot air corridor132. The pressure differential between the cooling air 18 a and the hotair 16 is maintained at a sufficient level to ensure there is no returnof hot air 16 through the racks. This is done by monitoring the amountof air flow in the rack room module 140 using the air flow sensor. Theamount of air flow is fed to the process control panel 137 b in theplant room 133. The process control panel 137 b then controls the fansin the air optimisation unit 122 and the various controllable vents inthe building (apart from the vents 142 in the data room doors, which areused to control the amount of cooling air fed to each cold aisle) sothat satisfactory air pressure is delivered to the air supply corridor123 to give a satisfactory air pressure differential and air flow in therack room module 140. The humidity of the air in the rack room module140 is monitored by the humidity level sensor and fed to the processcontrol panel 137 b. The process control panel 137 b then controls thehumidification apparatus in the air optimisation unit 122 so thatsatisfactory air humidity is delivered.

The building 100 operates differently depending on the temperature ofthe outside ambient air. This is done in order to allow the cooling air18 a to be between 18° C. and 24° C., whilst minimising the amount ofrefrigerant-based mechanical cooling that needs to be performed on theair by the cooling system in the air optimisation unit 122.

When the outside temperature is below 18° C., as shown in FIG. 14, theprocess control panel 137 b controls the cooling system in the airoptimisation unit 122 so that the cooling system is turned off. Theprocess control panel 137 b also controls the vents in the return airgrille 125 so that the vents on the grille 125 are open. This allowssome of the hot air 16 in the hot air corridor 132 to re-enter the airoptimisation unit 122. The rest of the hot air 16 escapes out of thebuilding 100 through hot air outlet grille(s) 146. I.e. there is partialextraction of ambient air 18 and partial re-circulation of hot air 16.The hot air 16 that re-enters the air optimisation unit 122 goes throughthe air mixing box (not shown) in the unit 122 and mixes with theambient air 18 being drawn into the air optimisation unit 122 throughthe ambient air intake grille 121. This results in warmer than ambientair passing from the air optimisation unit 122 into the air supplycorridor 123 and reaching the cold aisle(s) 144 of the rack roommodule(s) 140.

The temperature of the air at the rear of each row of racks in the rackroom module(s) 140 is monitored by the air temperature sensors and fedto the process control panel 137 b. Pressure measurements are alsotaken. The process control panel 137 b controls the vents 142 in thecold aisle doors in dependence on cooling demand and controls the fansin the air optimisation unit 122 and other vents so that a sufficientair flow is delivered from the air supply corridor 123 to the coldaisles in the rack room module(s) 140.

When the outside temperature is between 18 and 24° C., as shown in FIG.15, the process control panel 137 b controls the cooling system in theair optimisation unit 122 so that the cooling system is turned off. Theprocess control panel 137 b also controls the vents in the return airgrille 125 so that the vents on the grille 125 are closed. This meansthat no hot air 16 can re-enter the air optimisation unit 122. I.e.there is no re-circulation of hot air 16 and there is total ambient air18 extraction. All of the hot air 16 escapes out of the building 100through hot air outlet grille(s) 146.

The temperature of the air at the rear of each row of racks in the rackroom module(s) 140 is monitored by the air temperature sensors and fedto the process control panel 137 b. Pressure measurements are alsotaken. The process control panel 137 b controls the vents 142 in thecold aisle doors in dependence on cooling demand and controls the fansin the air optimisation unit 122 so that a sufficient air flow isdelivered from the air supply corridor 123 to the cold aisles in therack room module(s) 140 to a satisfactory temperature.

When the outside temperature is between 24 and 37° C., as shown in FIG.16, the process control panel 137 b controls the cooling system in theair optimisation unit 122 so that the cooling system is turned on andset to cool the cooling air 18 a leaving the air optimisation unit 122down to a maximum of 24° C. This is achieved by using the humidificationunit to cause adiabatic cooling of the air. At this stage norefrigerant-based active cooling is required. The process control panel137 b also controls the vents in the return air grille 125 so that thevents on the grille 125 are closed. This means that no hot air 16 canre-enter the air optimisation unit 122. I.e. there is no re-circulationof hot air 16 and there is total ambient air 18 extraction. All of thehot air 16 escapes out of the building 100 through hot air outletgrille(s) 146.

The temperature of the air at the rear of each row of racks in the rackroom module(s) 140 is monitored by the air temperature sensors and fedto the process control panel 137 b. The process control panel 137 b thencontrols the cooling air flow regime so that a sufficient air flow isdelivered from the air supply corridor 123 to the cold aisles.

When the outside temperature is above 37° C., as shown in FIG. 17, theprocess control panel 137 b controls the cooling system in the airoptimisation unit 122 so that the cooling system is turned on and set tocool the cooling air 18 a leaving the air optimisation unit 122 down toa maximum of 24° C. This is achieved by means of additionally usingDX-mechanical (refrigerant-based) cooling. The process control panel 137b also controls the vents in the return air grille 125 and hot airoutlet grille 146 so that the vents on the grille 125 are open and thevents on hot air outlet grille(s) 146 are closed. This ensures all thehot air 16 re-enters the air optimisation unit 122. I.e. there is totalre-circulation of hot air 16 and no ambient air 18 extraction. Theprocess control panel 137 b also controls the vents of ambient airintake grille 121 so they are closed. The hot air 16 goes through theair mixing box (not shown) in the air optimisation unit 122 and isre-cooled by the cooling system in the air optimisation unit 122.

The temperature of the air at the rear of the racks in the rack roommodule(s) 140 is monitored by the air temperature sensors and fed to theprocess control panel 137 b. The process control panel 137 b thencontrols the cooling air flow regime so that a sufficient air flow isdelivered from the air supply corridor 123 to the cold aisles.

In the event of the VESDA (Very Early Warning Smoke Detection Apparatus)system detecting a fire, the process control panel 137 b activates thefire suppression gas discharge canisters 136. Hence, gas is dischargedthrough the air optimisation unit 122 into air supply corridor 123. Atthe same time, the process control panel 137 b closes vents in the hotair outlet grille(s) 146 and opens vents in the return air grille 125 toensure the air inside the building 100 is re-circulated. The VESDAsystem may as an initial step cause air flow into and/or out of thebuilding to be ceased and to operate the building in an airre-circulation mode. On the one hand, if smoke is no longer detectedthen there may be no need to release the fire suppression gas. On theother hand, if smoke continues to be detected then it may be deducedthat the cause of the smoke is within the building and not an externalfire. Fire suppression is then released only as necessary.

As the fire suppression gas rapidly expands, release vents (not shown)in the building 100 are activated to maintain the building integrity.

In the event of a power cut to the external power supply of the building100, the uninterruptible power supply 139 a and back-up batteries 139 bare turned on and can provide clean power to allow continuous operationof the racks 143 and other essential services for 10 minutes.

When a data centre building 100 is required, the different modules canbe individually delivered on trucks, such as 40 foot articulated or flatbed trucks. The buildings are typically less than 4.2 m high andtherefore are readily transported via road or rail. The modules can thenbe craned into place using integral lifting eyes (not shown) on themodules or using slings. The building 100 can be sited on a flat area ofconcrete. Alternatively, the building 100 can be placed on concreteblockwork if the site is not level or if the level of the building 100is to match an existing building level.

The building 100 is then connected to the existing site drainage system,telecommunications supply, water supply and electrical power supply.Alternatively, a supplementary power generation unit can be added. Thebuilding 100 can also be connected to the existing building managementsystems, security systems or fire alarm systems of the site.

When it is required to relocate the data centre building, this can bedone by disconnecting the external power supply etc. and individuallycraning modules onto trucks to be delivered and re-set up elsewhere.

In an alternative embodiment, shown in FIGS. 21 and 22, each module hasthe dimensions of an ISO shipping container and is constructed so thatit may be transported as a shipping container. ISO shipping containerscome in a range of lengths and heights but are all 2259 mm wide betweenthe corner fittings (measured from the centre of the hole in thefitting). Common lengths are approximately 6 m, approximately 12 m andapproximately 14 m.

Each module comprises a steel framework, with the vertical parts of thisframework including an integrated drainage system (not shown). Thewalls, roof and floor of each module are made of corrugated steel.Although in this embodiment the dimensions of the modules are differentto those in the embodiments described above, the way the modules arefitted out and connected together is substantially the same. The layoutof a data centre built using this type of module can therefore take anyof the same forms as a data centre built using the modules shown inFIGS. 3-17.

FIG. 21 shows a data centre 200 constructed from container-sizedmodules. It comprises an air optimisation module 220, a plant roommodule 230, eight rack room modules 240, and a hot aisle unit 250. Anend wall of the air optimisation module 220 and an end wall of one ofthe rack room modules 240 have been replaced with an air intake 260 andan exhaust air outlet 270 respectively. One or more of the panelsforming an external wall of the data centre 200 may include a door (notshown). FIG. 22 is an exploded view of the data centre of FIG. 21.

A further embodiment of the invention is illustrated by FIGS. 23 and 24.FIG. 23 shows the layout of a story of a building into which three datacentres 300 a, 300 b and 300 c according to the invention have beeninstalled. Part 380 of the story is not taken up by a data centre andthis may be used for another purpose such as office space or storage.Data centres 300 a and 300 b each comprise two air optimisation rooms320, two plant rooms 330, a rack room 340 and an air supply corridor350. Data centre 300 c comprises an air optimisation room 320, a plantroom 330, a rack room 340 and an air supply corridor 350. Holes (notshown) have been made in the walls of the building to serve as intakesfor outside air and outlets for exhaust air.

Data centres 300 a, 300 b and 300 c have been constructed by installingpartitions into a space in the existing building. The partitions areformed using a kit of parts consisting of metal girders and insulatedsteel panels. FIG. 24 shows a partially constructed data centre 300according to this embodiment of the invention. A framework 400 builtfrom the metal girders has been constructed in a space within abuilding. The space has a concrete floor. Wall panels 410 and ceilingpanels 420 are attached to this framework. Panels including dampers (notshown) are positioned so as to line up with the intake and outlet holesin the exterior walls of the building. Ladder racks 430 are suspendedabove the ceiling panels 420 to support the cabling and other mechanicaland electrical services that are provided to the racks. The panels arearranged to form a data centre having an air optimisation room, a plantroom, a rack room, and an air supply corridor. The layout of the datacentre is the same as in other embodiments of the invention. The rackroom includes separate hot aisles and cold aisles in the samearrangement as in the other embodiments of the invention.

For countries in the Northern Hemisphere, it is anticipated that theambient air temperature will be below 37° C. 97% of the time. Hence, forthese countries, the building 100 can operate in either of the firstthree modes of operation described for 97% of the time. Hence, for 97%of the time, the building 100 only uses ambient airflow andhumidity-controlled cooling and does not need to rely onrefrigerant-based cooling. This dramatically reduces the energyconsumption of the data centre building 100.

Even in the hottest, driest or most humid locations on the planet, thebuilding can still operate in the first or second mode a significantproportion of the time and therefore can use only air flow cooling. Evenat temperatures of up to 37° C., the building 100 will operate in thethird mode of operation and therefore can still utilise efficient meansof cooling.

The most common benchmark of energy efficiency for data centres is powerusage efficiency (PUE). In this embodiment, this may conveniently bedefined as the total energy used by the data centre divided by theenergy deployed to the racks 143. Typical prior art data centres have aPUE of greater than 1.5. A data centre building 100 of the presentinvention could have a PUE of less than 1.2 for most parts of the world.This figure would increase for hotter parts of the world whererefrigerant-based mechanical cooling has to be used more often.

In the above-described embodiments, the securable door allowingpersonnel access from the air supply corridor 123 to the cold aisle 144of the rack room module 140 includes an adjustable air intake means inthe form of an air intake grille 142 including vents. The door can beconfigured differently to provide cooling air 18 a into the cold aisle144 via the doorway. FIGS. 19 a, b, c and d show such a door 170. Thedoor is mounted in a door frame 170 a. The door frame is hinged to theinternal wall 141 of the room module 140, adjacent a door hole in theinternal wall, along a first side 171 of the door frame. The first side171 of the door frame is the side furthest from the air optimisationunit 122. The door frame 170 a is hinged to a first side of an airintake grille 172 along a second opposite side of the door frame. Thegrille is attached to the internal wall 141 by a hinge along a secondopposite side of the grille. The hinge is also slidable along theinternal wall 141. When the door frame 170 a is in a closed position, asshown in FIGS. 19a and 19b , the door frame and grille 172 lie in linewith each other and parallel to the internal wall 141, such that thedoor and door frame covers the hole in the internal wall 141 and thegrille lies flush behind the wall 141. The door 170 can be opened fromthe door frame 170 a when the frame is in the closed position. When thedoor frame is in an open position, as shown in FIG. 19d , the door frameis hinged away from the hole in the wall 141. The grille pivots withrespect to the door frame and by the hinge on the internal wall 141 andthe internal wall hinge slides along the internal wall 141 such that thesecond side of the grille remains in contact with the internal wall 141and the first side of the grille remains connected to the second side ofthe door frame. Hence, an angled path against the door and door frameand through the grille is provided for air in the air supply corridor123. The door arrangement therefore acts as a variable air inlet scoop.The air thus flows from bottom to top as shown in FIGS. 19c and d (theair supply corridor being below the doorway in the Figures). The doorcan also be opened from the door frame in the open position, as shown inFIG. 19c . The door frame and grille can also be positioned in a numberof intermediate positions between the fully open and fully closedpositions described above. The door arrangement could of course also beused in a reverse configuration, so that first side of the door frame isthe side nearest the air optimisation unit with air flowing from the topto bottom as shown in FIGS. 19c and d (the air supply corridor beingbelow the doorway in the Figures).

FIG. 20 shows yet another embodiment of a door 180 for allowingpersonnel access therethrough whilst also providing a means forcontrolling airflow through the door whilst the door is in its closedposition. The door thus includes adjustable air intake means in the formof a vent 181 having a number of vertical blades 182 arranged in a row.The blades are each mounted for rotation about a vertical axis, suchthat the vent may be moved between closed and open positions by means ofrotation of the blades. The blades 182 are arranged such that pairs ofadjacent blades are arranged to rotate simultaneously in oppositedirections. Having such an arrangement facilitates better control of theair-flow in comparison to the case where all blades rotate in the samedirection. Two motors (not shown) are arranged to move the blades 182,one motor for the odd-numbered blades and one motor for theeven-numbered blades (counting from left to right). (It will beappreciated that one motor could be arranged to control all the blades.)The area covered by the blades extends across about 80% of the width ofthe door. The area covered by the blades 182 extends across about 60% ofthe height of the door. The effective open area when the vent 181 isfully open is about 1.4 m². The vent is arranged such that in the eventof a failure the vent fails “open”.

The door arrangement includes a flexible cable 183 that runs from themotors to the hinge 184 side of the door and then onto the structure ofthe adjacent wall 185. The cable carries a control signal which controlsthe operation of the motors. The control signal is preferably set independence on measured characteristics of the air in or immediatelyoutside the building.

Whilst the present invention has been described and illustrated withreference to particular embodiments, it will be appreciated by those ofordinary skill in the art that the invention lends itself to manydifferent variations not specifically illustrated herein. By way ofexample only, certain possible variations will now be described.

The air supply corridor 123 from the air optimisation unit 122 to therack room module(s) 140 may be independent of the passageway leading tothe rack room module(s) 140. The air may be supplied at least partiallyvia an under-floor duct.

The data centre building 100 need not be constructed from separatemodules.

Moreover, cooling air may be transported through a wall of the rack roomvia one or more apertures or passageways in the wall that are notarranged to permit personnel access. There may be an access door to therack room that is not part of the intended path for cooling air.

The racks and aisles defined by the racks need not be straight and/orrectangular in plan-view.

Where in the foregoing description, integers or elements are mentionedwhich have known, obvious or foreseeable equivalents, then suchequivalents are herein incorporated as if individually set forth.Reference should be made to the claims for determining the true scope ofthe present invention, which should be construed so as to encompass anysuch equivalents. It will also be appreciated by the reader thatintegers or features of the invention that are described as preferable,advantageous, convenient or the like are optional and do not limit thescope of the independent claims. Moreover, it is to be understood thatsuch optional integers or features, whilst of possible benefit in someembodiments of the invention, may not be desirable, and may therefore beabsent, in other embodiments.

The invention claimed is:
 1. A method of cooling racks of items ofelectronic equipment in a data centre building, wherein the racks ofitems of electronic equipment are accommodated in a plurality of rackstorage areas on a floor in the data centre building, and the datacentre building comprises: a plurality of cold aisles interleavedbetween a multiplicity of hot aisles, wherein adjacent hot and coldaisles are separated by at least one rack storage area, and at least oneaccess corridor, wherein the at least one access corridor and the coldaisles facilitate personnel access to the plurality of rack storageareas; said method of cooling comprising the following steps: operatingone or more controllable air circulation devices comprising one or morefans, upstream of the racks of items of electronic equipment to causethe transporting of air, via a humidity-based cooling unit, to the coldaisles and thus to the racks of items of electronic equipment, the aircomprising one of (a) ambient air from outside the data centre buildingand (b) ambient air from outside the data centre building andrecirculated air; removing the air from the racks of items of electronicequipment; and at least partially exhausting the removed air from thedata centre building; and wherein said transporting of air to the racksof items of electronic equipment is performed in a manner wherein saidair is transported above the floor via the at least one access corridorto the plurality of cold aisles, and said transporting of air to theracks of items of electronic equipment and said removing the air fromthe racks of items of electronic equipment causes air to flow past theitems of electronic equipment at a rate high enough to cool the items ofelectronic equipment.
 2. A method according to claim 1, wherein the oneor more controllable air circulation devices cause circulation of theair to the rack storage areas under a controlled pressure regime, thepressure regime comprising maintaining differential pressures as betweenthe pressure in a cold aisle and the pressure in a hot aisle, therebyencouraging air flow from the cold aisle to the hot aisle.
 3. A methodaccording to claim 1, wherein each rack of items of electronic equipmentcomprises a multiplicity of slots for housing the items of electronicequipment and the method comprises exhausting air from the data centrebuilding at a rate selected from the group consisting of a) at least0.00024 m³s⁻¹ per slot and b) at least 0.002 m³s⁻¹ per slot.
 4. A methodaccording to claim 1, wherein a refrigerant-based cooling step is notrequired to cool the items of electronic equipment for at least 97% ofthe time during which the data centre is operated.
 5. A method accordingto claim 1, wherein the cooling air has a maximum threshold temperatureupstream of the racks of items of electronic equipment of 37 degreesCelsius.
 6. A method according to claim 1, wherein the at least oneaccess corridor is separate from both the cold aisles and the hot aislesand facilitates personnel access from outside the data centre buildingto one of the rack storage areas.
 7. A method according to claim 1,wherein all the removed air is exhausted to outside the data centrebuilding.
 8. A method of cooling items of electronic equipment, whereinthe items of electronic equipment are accommodated in racks arranged ina plurality of rows of racks on a floor in a data centre building, saidplurality of rows of racks defining a plurality of cold aislesinterleaved between a multiplicity of hot aisles, adjacent hot and coldaisles being separated by at least one row of racks, the data centrebuilding including at least one access corridor to the plurality of coldaisles, the at least one access corridor and the cold aisles togetherproviding access to the plurality of rows of racks, and the data centrebuilding includes an air optimizer system, located upstream of the itemsof electronic equipment, the air optimizer system comprising one or morefans and a humidity-based cooling unit, said method comprising the stepsof: supplying air comprising one of (a) ambient air from outside thedata centre building and (b) ambient air from outside the data centrebuilding and recirculated air to the air optimizer system, using thehumidity-based cooling unit of the air optimizer system to cool the air,using the one or more fans of the air optimizer system to transport thecooled air from the air optimizer system, above the floor, to the coldaisles, and thus to the items of electronic equipment, at least some ofthe cooled air being transported above the floor via the at least oneaccess corridor, and at least partially exhausting, from the data centrebuilding, air which has been heated by the items of electronicequipment, whereby the air transported to the cold aisles cools theitems of electronic equipment under the control of the air optimizersystem.
 9. A method according to claim 8, wherein the one or more fanscause circulation of the air to the racks under a controlled pressureregime, the pressure regime comprising maintaining differentialpressures as between the pressure in a cold aisle and the pressure in ahot aisle, whereby air flow is encouraged from the cold aisle to the hotaisle.
 10. A method according to claim 8, wherein each rack of items ofelectronic equipment comprises a multiplicity of slots for housing theitems of electronic equipment and the method comprises exhausting airfrom the data centre building at a rate selected from the groupconsisting of a) at least 0.00024 m³s⁻¹ per slot and b) at least 0.002m³s⁻¹ per slot.
 11. A method according to claim 8, wherein arefrigerant-based cooling step is not required to cool the items ofelectronic equipment for at least 97% of the time during which the datacentre is operated.
 12. A method according to claim 8, wherein thecooling air has a maximum threshold temperature upstream of the racks ofitems of electronic equipment of 37 degrees Celsius.
 13. A methodaccording to claim 8, wherein the at least one access corridor isseparate from both the cold aisles and the hot aisles and facilitatespersonnel access from outside the data centre building to at least oneof the rows of racks.
 14. A method according to claim 8, wherein all theair which has been heated by the items of electronic equipment isexhausted to outside the data centre building.
 15. A method of operatinga data centre, wherein the data centre comprises a plurality of racks ofitems of electronic equipment requiring cooling in a plurality of rackstorage areas, said plurality or racks so arranged to form a pluralityof cold aisles interleaved between a multiplicity of hot aisles,adjacent hot and cold aisles being separated by at least one rackstorage area, a floor defining a floor-level beneath the plurality ofracks of items of electronic equipment, an access corridor whichtogether with the cold aisles provides access to the plurality of rackstorage areas, and an air optimizer system comprising one or morecontrollable air circulation devices comprising one or more fans, and ahumidity-based cooling unit, the air optimizer system being positionedupstream of the racks of items of electronic equipment, wherein themethod comprises: a) using the air optimizer system to cool the racks ofitems of electronic equipment by: i) operating the one or morecontrollable air circulation devices to transport air along an air flowpath which extends from the air optimizer system to the racks of itemsof electronic equipment, the air comprising one of (a) ambient air fromoutside the data centre building and (b) ambient air from outside thedata centre building and recirculated air, wherein the air flow path isentirely located above floor-level and, for at least 90% of the distancealong the air flow path, has a cross-sectional area greater than 2square meters, ii) cooling the air with the use of the humidity-basedcooling unit, iii) removing air from the racks of items of electronicequipment; and iv) at least partially exhausting the removed air fromthe data centre building; whereby the air A) transported along the airflow path to the racks of items of electronic equipment, and B) removedfrom the racks of items of electronic equipment is moved at a rate highenough to cool the items of electronic equipment.
 16. A method accordingto claim 15, wherein the air flow path includes at least part of the atleast one access corridor.
 17. A method of operating a data centrebuilding comprising: using an air optimizer system comprising anadiabatic evaporative cooler to provide conditioned air by adiabaticcooling of air comprising one of (a) ambient air from outside the datacentre building and (b) ambient air from outside the data centrebuilding and recirculated air; transporting under the control of the airoptimizer system the conditioned air from the air optimiser system toracks of items of electronic equipment arranged in rows on a floor inthe data centre building, the air being transported above the floor viaan air flow path comprising (i) an air supply corridor and (ii) a coldaisle disposed between two rows of racks of electronic equipment, theair supply corridor and the cold aisle providing personnel access to thetwo rows of racks of items of electronic equipment; using theconditioned air to cool the items of electronic equipment by causing theconditioned air to flow from the cold aisle to an adjacent hot aisleseparated from the cold aisle by one of the rows of racks of items ofelectronic equipment, the conditioned air absorbing heat from the itemsof electronic equipment as it flows from the cold aisle to the hotaisle; and exhausting at least some of the heated conditioned air fromthe data centre building.
 18. A method according to claim 17, whereinfor at least 90% of the distance along the air flow path, the air flowpath has a cross-sectional area greater than 2 square meters.
 19. Amethod according to claim 17, wherein each rack of items of electronicequipment comprises a multiplicity of slots for housing the items ofelectronic equipment and the method comprises exhausting air from thedata centre building at a rate selected from the group consisting of a)at least 0.00024 m³s⁻¹ per slot and b) at least 0.002 m³s⁻¹ per slot.